Dunno what makes you call that 'virtue signaling', aside from maybe some acute early onset dementia, but they mark it 'Earth' to indicate the intended lifespan of the company, i.e. beyond that of our time living on this rock alone. It's got nothing to do with 'signaling' anything, much less about the 'virtues' of Spyderco as a company. It's like Babe Ruth pointing beyond the stands before taking his batting stance, not whatever goblin you imagine to be lurking in the stamp
That makes no sense at all, even if(?) they claim that as a reason. Where else but on Earth would those knifes be made? Sophomoric.